The present invention relates to a system and method for generating a cascode current source bias voltage.
Current sources operate in electronic circuits to provide or receive an electrical current. An ideal current source has a large output impedance such that it provides a constant current output regardless of the voltage applied across the ideal current source. Thus, an ideal current source has infinite output impedance. In practical application, however, all current sources have a finite output impedance such that the current output by a current source inherently varies in accordance with variations in the voltage across the current source, due to the finite output impedance of real-world components. Certain circuit structures may enable improved output impedance, but may increase voltage overhead, and may be less robust against power supply variations.
An ideal current source, however, has a relatively low voltage overhead, such that the minimum voltage Vout_min at which the current source can operate is low. Further, an ideal current source is robust against power supply variations, such that variations in power supply voltages have a lower impact on the operation of the current source.
In many different fields, therefore, there is a desire for a current source having a relatively high output impedance, while still having a relatively low minimum voltage Vout_min at which the current source can operate, and while still being robust against power supply variations.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known to a person of ordinary skill in the art.